Electronic devices—such as mobile devices, mobile phones, tablet computers, music and multi-media players, watches, gaming devices, and other handheld, wearable or portable devices—have one or more buttons such as home buttons, power buttons, or buttons that perform other functions.
These buttons typically are formed of multiple components arranged in a button assembly that may include button portion which is depressed by the finger or thumb of a user, and one or more components beneath the button portion. FIG. 1A illustrate an example of a typical button assembly 10 within a housing 12, wherein the button assembly 10 includes a button portion 14. One the opposing end of the button housing 12, a tactile switch 16 may be provided that can contact a flexible circuit portion 20 that can be affixed through a pressure sensitive adhesive (PSA) 21 to a button bracket 22, in this example.
In this example in FIG. 1A, a metal or plastic shim 18 is attached to the interior side of the button portion 14 using a pressure sensitive adhesive.
The shims 18 shown in FIGS. 1A-1C can play an important role in proper tactile feel of a button assembly 10 as experienced by a user—although some buttons can be formed without shims. Typical button click lengths/travel ranges can span from 0.12 mm to 0.28 mm, and shim thicknesses can have tolerances of approximately 0.01 mm in one example.
As recognized by the present inventor, proper tactile feel of a button assembly 10 for user is achieved when, as shown in FIG. 1A, the shim 18 is precisely sized in the gap between the tactile switch 16 and the interior surface of button portion 14—so that there is not excessive play for instance when shim 18 is too thin as shown in FIG. 1B such that the button assembly 10 rattles or feels loose to the user because there is a small gap present between the tactile switch 16 and button portion 14. Conversely, if the shim 18 is too thick as shown in FIG. 1C, then the tactile switch 16 becomes preloaded and the button 14 travel is too short which also is problematic for tactile feel.
As recognized by the present inventor, there are variations in the manufactured thicknesses of each part 12, 14, 16, 20, 22 within a button assembly 10, including variations in the thickness of a conventional plastic shim 18, and these variations can result in either a small gap in the button assembly 10 such as shown in FIG. 1B, or a button tactile switch preload condition in the button assembly 10 such as shown in FIG. 1C.
Accordingly, as recognized by the present inventor, what is needed are improved button shims for buttons of electronic devices.